Method and apparatus for preventing relative motions

ABSTRACT

A method for preventing the relative movement beyond a predetermined magnitude between a driving band set in motion by a driving motor and between a device, such as a torch, clamped on the band and adapted to carry operating instruments thereon, wherein the relative movement arising between the band and the operating device clamped thereon, is secured and signals are fed for stopping the driving motor of the band upon said relative movement exceeding a predetermined magnitude. The invention also discloses a torch cutting apparatus comprising a driving motor, a metal band coupled to the driving motor and adapted to move in a predetermined path, an upper carriage carrying a torch cutting device, an arrangement for clamping the upper carriage onto the band at a predetermined point according to the pattern to be cut, means for sensing a relative movement between the band and the upper carriage and developing a signal when the relative movement exceeds a predetermined magnitude, and an arrangement responsive to the signal and causing a turning off of the driving motor.

United States Patent [1 1 Roeder 1 Sept. 18, 1973 METHOD AND APPARATUSFOR PREVENTING RELATIVE MOTIONS George Roeder, Frankfurt/M ain, Germany[75] lnventor:

[73] Assignee: Messer Griesheim GmbH, Frankfurt am Main, Germany [22]Filed: June 19, 1972 [21] Appl. No.: 264,042

Primary Examiner-Gerald A. Dost AttorneyErnest F. Marmorek 57 ABSTRACT Amethod for preventing the relative movement beyond a predeterminedmagnitude: between a driving band set in motion by a driving motor andbetween a device, such as a torch, clamped on the band and adapted tocarry operating instruments thereon, wherein the relative movementarising between the band and the operating device clamped thereon, issecured and signals are fed for stopping the driving motor of the bandupon said relative movement exceeding a predetermined magnitude. Theinvention also discloses a torch cutting apparatus comprising a drivingmotor, a metal band coupled to the driving motor and adapted to move ina predetermined path, an upper carriage carrying a torch cutting device,an arrangement for clamping the upper carriage onto the band at apredetermined point according to the pattern to be cut, means forsensing a relative movement between the band and the upper carriage anddeveloping a signal when the relative movement exceeds a predeterminedmagnitude, and an arrangement responsive to the signal and causing aturning off of the driving motor.

9 Claims, 5 Drawing Figures PATENIEDSEPI ems SHEET 1 OF 2 QM N FIELD OFTHE INVENTION The present invention relates to a method and apparatusfor preventing a relative movement beyond a permissible magnitudebetween a driving means, such as a driving or actuating metal strip andan instrument carrying means, such as the upper carriage of a torchcutting machine.

BACKGROUND OF THE INVENTION In torch cutting machines inwhicha pluralityof 1 electric means, or some other manner, along acurve corresponding tothe cutting pattern. It is necessary that the upper carriage is movedback and forth over an exact path as controlled by the rotationalmovement of a drive. Such drive of the upper carriage is; performed byan endless transporting means which can be in the form of a metal or apreferably vertically mounted steel strip or conveyor bandpln contrastto other endless transporting or conveying means, such as chain orcable, the preferred metal band remains rigid and stiff in the directionof its surface expansion and it will not sag downward. The metal band isusually guided over a pair of guide rollers of driving roller.

On such metal band either on its front or back section the uppercarriages are clamped according to the contours of the pattern which areto be cut out by the torch device. By moving the metal band the uppercarriages will undergo similar movement,that is, mounted on theoppositely lying band section moved in opposite direction withrespect toeachother.

Inasmuch as the upper carriages carrying the cutting,

torch must be secured on various places on the steel band in order thatthe upper carriages with their cutting torches could reach any desiredcontour, obviously,

theremust be a coupling between the upper carriage and the metal band,which is usually a clamping arrangement. Inasmuch as the clampingarrangement represents a positive force coupling but not a spatialphysical connection between the metal strip and the upper carriage,therefore, there will be a relative movement between such portions when,for instance, large bearing frictions or path frictions arise during thelong rail path on which the upper carriage travels. Suchrelativemovement between the metal strip and the upper carriage will lead to asituation that the upper carriage with the torch cutting device mountedthereon undergoes a movement which doesnot any more correspond to themovement prescribed by the control pattern so that the workpiece whichis being cut out will become too small and therefore a waste isproduced. Or, for ex ample, in case a cut out piece must be producedfrom a plate, then due to the relative movements described above the cutSUMMARY OF THE INVENTION It is, therefore, an object of the presentinvention to provide a method and apparatus for reliably sensing therelative movement between the driving band and the upper carriage of atorch cutting apparatus and'turning off of the driving means of saiddriving band in the which one is the riage is sensed by a device whichwhen the relative movement exceeds a predetermined magnitude will causea turning off of the driving means of the band so that an immediatestopping of the band will give the opportunity to correct the defectivecondition and avoid producinga waste by resetting the apparatus in thedesired position and thereby producingworkpieces according to apredetermined pattern and control program.

According to the present invention in a torch cutting apparatus a metaldriving band is provided on which an upper carriage is clamped whichcarries the torch cutter. The upper carriage according to the presentinvention is provided with a sensing device sensing the rela tivemovement between the metal band and the clamped upper carriage and whichis coupled to a switching device causing a turning off of the drivingmeans of the band in the event there is an excessive relative movementbetween the band and the upper carriage.

In a preferred embodiment of the present invention the sensing device isa sensor having a sharp point which is in abutting relationship with themetal band. The sensor itself is coupled to a pin which is rotatablyjoumalled within the upper carriage and which is provided with aswitching rod operating a switching device. This is an extremely simpleand reliable construction of the sensor means.

In order that the sensor means could abut against the metal band exactlyaccording to the present invention, the sensor is carried by a leafspring which couples the sensing tips to apin and which in turn, asmentioned above, is journalled within the upper carriage.

According to the present invention the switching rod mounted forrotation with the aforementioned pin at one end which is opposite to theend operating the switching device is coupled by means of a spring tothe upper carriage. Such spring causes the centering of the switchingrod in a null position automatically as soon as the clamping of theupper carriage with the band ceases or 'inthe absence of a relativemovement between the band and the upper carriage.

The switching arrangement may comprise according to the presentinvention camming means and/or electrical switching devices, such asmicro-switches or other 'types of switching elementswhich are operableby DESCRIPTION OF THE DRAWINGS The invention will become more readilyapparent from the following description of a preferred embodimentthereof shown, by wayof example, in the accompanying drawings, in which:

FIG. 1 is a front view of an upper carriage of a torch cutting machine,partly in section;

FIG. 2 is a top view in the direction of the arrow A on the metal bandof FIG. 1;

FIG. 3 is a side view of the upper carriage viewed in the direction ofthe arrow B in FIG. 1;

FIG. 4 is an enlarged illustration of the cut-out portion C of FIG. 3;

FIG. 5 is a top view in the direction of the arrow D according to FIG.4.

DESCRIPTION OF THE PREFERRED EMBODIMENT With reference to FIG. 1 it isseen that the upper carriage of a torch cutting machine which is notshown itself to avoid a crowding of the portions to which the inventionpertains, is arranged for movement along a path represented by the rails17,18 by means of its rollers 11-16. The paths or rails 17,18 aremounted on a rail mount 19 of the torch cutting device which itself isnot shown and, more particularly, the rail 17 is provided on the upperside of the carrier while the rail 18 is provided on the lower side ofthe carrier 19.

The upper carriage 10 which carries a torch cutting device 20 is drivenin the illustrated embodiment by a steel conveyor band 21 which ismounted in its operational position in a vertical direction, that is, inits front view as shown in F1G.l the belt itself faces its viewer withits wide side. With reference to FIG.2, which illustrates the steelconveyor band 21 in its entirety, it is seen that the band 21 is guidedover a pair of guide rollers 22,23 of which, for example, the roller 22is the driving roller and is driven by a motor 24. According to thedesired control pattern, the motor 24 is rotated one way or the otherand, consequently, either the front 25 or back 26 band section moves tothe right or to the left.

On the steel conveyor band 21 either on its front 25 or back 26 portionan upper carriage 10 or a plurality thereof is mounted at a positionwhich is predetermined by the desired contour of the pattern to be cutout.

The securing of the upper carriage to the band 21 is performed by aclamping arrangement as more particularly can be seen in FIGS. 3-5.

The upper carriage 10 itself contains the clamping arrangement in theform of a clamping jaw carrier 27 as well as a front clamping jaw 28 anda back clamping jaw 29' which are coupled with each other by means of anoperating shaft 31 having a thread 30 thereon. The shaft 31 is rotatedby means of a lever 32 which, when moved or rotated in clockwisedirection, causes the front movable clamping jaw 28 to move in thedirection of the clamping jaw carrier 27 and in the direction of thefront section 25 of the steel band 21, so that there will be a forcecoupling between the front section of the band 21 and the upper carriage10, as seen in F IG.4. By rotating the arm 32 in counter clockwisedirection, in another set-up, the back clamping jaw 29 becomes clampedonto the back band section 26. In order to prevent a rotation orshifting of the clamping jaws 28 or 29 during the clamping process, thejaws 28 and 29 are provided by guide pins 33 and 34 which are inoperative relationship with corresponding guide recesses 35 and 36 inthe clamping jaw carrier 27 when the respective clamping jaw isoperational.

The clamping jaw carrier 27 is provided also with a sensing arrangement37 which comprises a pair of sensors 38 and 39 each being provided witha sharp end point. Such sensors 38 and 39 are carried by leaf springs 40and 41, respectively, which are secured by screws to a bolt 42 which isjournalled on ball bearings in the clamping jaw carrier 27. On bolt 42 aswitching rod 43 is secured, one lever arm 43a of which extends into theoperating region of a switching arrangement 44 while the other lever arm43b of which is coupled with a spring means 45 secured to the clampingjaw carrier 27.

The switching arrangement 44 itself in the illustrated embodimentcomprises a pair of micro switches 46,47 which are secured onto theclamping jaw carrier 27.

By means of the above-described sensing arrangement 37 and switchingarrangement 44 the relative movement between the steel band 21 andbetween the clamped upper carriage 10 thereto is prevented if occursbeyond a permissible value.

The operation of the arrangement according to the present invention isas follows:

During the clamping of the front clamping jaw 28 onto the front section25 of the band 21 a ball spacer switch 49 which is biased by a spring 48becomes pressed back in the direction of the clamping jaw carrier 27.The ball spacer switch 49 is provided in order to prevent an undesiredoperating of the sensors 38 and 39 by the front 25 or back 26 section ofthe band 21 when the clamping jaw carrier 27 has not been clamped onthem yet.

Simultaneously with the pressing back of the ball spacer switch 49, thesensor 38 with its pointed tip will abut against the force of the leafspring 40 in the direction of the arrow B (F164) and due to the force ofthe leaf spring the tip of the sensor 38 becomes pressed against thefront section 25 of the band 21.

Then when the band 21 is moved by the motor 24 as controlled by thecontrol devices, not shown, of the torch cutting apparatus, it willcause a simultaneous movement of the upper carriage 10.

In the event there is a large relative movement between the band 21 andthe clamping jaw 28 or clamping jaw carrier 27 due to the largetraveling path or bearing frictions, then the sensor 38 pressed againstthe band 21 will become carried by the band 21 to a certain extent alongthe direction of the band movement H (FIG.5) and, as a result, the bolt42 will be rotated about its axis 42a as seen by the curved arrows inFIGS and, the switching rod 43 becomes deflected from its null positionwhereupon the spring 45 which serves to stabilize the switching rod 43in its null position along with the sensors 38,39 becomes tensionedadditionally.

The pivoting movement of the lever arm 43a of the switching rod 43causes an actuation of the switch 46, which is an ordinary micro switch,and which in turn will cause an interruption of the movement of the band21 by turning off the motor 24. Simultaneously a warning signal can beoperated by the switch 46. 7

After removing the source of error or defect and after shortly openingup of the clamping jaw 28, the torch cutting apparatus can be set backagain into operation. The sensor 38 and the switching rod 43 returnagain into their null positions under the returning effect of the spring45 which comes into play upon the releasing of the clamping for a shorttime.

In the event the upper carriage band is mounted not on the front section25 of the band 21 as above described, but it is mounted on the backsection 26 of the band 21, then during a relative movement the sensor 39is also moved along a path H similarly as described with respect tosensor 38 and causes an appropriate rotation of the switching rod 43,then the switch 46 becomes actuated and the band 21 becomes stopped bythe turning off of the motor 24.

Since the relative movements occurring within the apparatus willdirectly affect the driving means 24 of the band 21 as soon as theyarise, the lever arm 43a of the switching rod 43 is constructed anddimensioned to have such a length that upon exceeding the permissiblemagnitude by the relative movement within the apparatus, it will thenand only then, cause an actuation of the switches 46 or 47 by movingthrough the appropriately designed switching path G as illustrated inFIGS.

It is within the scope of the present invention that the relativemovement of the sensors 38 or 39 and of the switching rod 43 can be madeto cause a variation in a capacitance, inductance or ohmic magnitude,whereupon such magnitudes by virtue of their arrangement in a controlcircuit, could cause the delivery of control signals to other circuitparts and to the motor 24. A change of this magnitude could cause, forinstance, a change in the state of a switching circuit or switchingelement, which in turn could be connected to control the motor 24driving the band 21 and/or operate also a warning device.

I wish it to be understood that I do not desire to be limited to theexact details of construction shown and described, for obviousmodifications will occur to a person skilled in the art.

Having thus described the invention, what I claim as new and desire tobe secured by Letters Patent, is as follows:

1. A method for preventing the relative movement beyond a predeterminedmagnitude between a driving band set in motion by a driving means andbetween a device clamped on the band and adapted to carry operatinginstruments thereon comprising the sensing of the relative movementarising between the band and the operating device clamped thereon,feeding signals for stopping the driving means of the band upon saidrelative movement exceeding a predetermined magnitude.

2. A torch cutting apparatus comprising a driving means, a metal bandcoupled to said driving means and adapted to move in a predeterminedpath, an upper carriage carrying torch cutting means, means for clampingsaid upper carriage on said band at a predetermined point according tothe pattern to be cut, means for sensing a relative movement betweensaid band and said upper carriage and developing a signal when saidrelative movement exceeds a predetermined magnitude, and meansresponsive to said signal and causing a turning off of the drivingmeans.

3. The torch cutting apparatus as claimed in claim 2, wherein saidsensing means comprises at least one sensor device having a pointedsensing tip adapted to abut against said band, a switching rod mountedfor rotation about a pin means, means for coupling said pin means withsaid switching rod whereby a movement of said sensor tip means with saidband causes a rotation of said pin means and a displacement of saidswitching rod over a switching path.

4. The torch cutting apparatus as claimed in claim 3, wherein saidsensing means comprises leaf spring means, said sensor tip means beingmounted on said leaf spring means coupling said sensor tip means withsaid pin means.

5. A torch cutting apparatus as claimed in claim 3, wherein saidswitching means comprises an electrical switch means mounted for sensinga displacement of said switching rod means over said switching path.

6. The torch cutting apparatus as claimed in claim 5, wherein saidelectrical switch means is a microswitch means placed along saidswitching path and being operable by said switching rod means when saidswitching rod means is displaced over said switching path, saidswitching path being dimensioned to correspond to the permissiblemagnitude of relative movement.

7. The torch cutting apparatus as claimed in claim 5, wherein saidelectrical switch means is an electronic element undergoing a change inits electrical magnitude in response to the displacement of saidswitching rod over said switching path and developing a signal inresponse to such change of its electrical magnitude to control theoperation of said driving means.

8. The torch cutting apparatus as claimed in claim 3, wherein a springmeans is provided for coupling an end portion of said-switching rod tosaid upper carriage means for fixing said switching rod in a nullposition in absence of a relative movement between said upper carriageand said band.

9. The torch cutting apparatus as claimed in claim 2, wherein saidsensing means comprises photo sensing means for sensing the relativemovement between said upper carriage means and said band and developinga signal which upon exceeding a predetermined magnitude will turn offsaid driving means.

1. A method for preventing the relative movement beyond a predeterminedmagnitude between a driving band set in motion by a driving means andbetween a device clamped on the band and adapted to carry operatinginstruments thereon comprising the sensing of the relative movementarising between the band and the operating device clamped thereon,feeding signals for stopping the driving means of the band upon saidrelative movement exceeding a predetermined magnitude.
 2. A torchcutting apparatus comprising a driving means, a metal band coupled tosaid driving means and adapted to move in a predetermined path, an uppercarriage carrying torch cutting means, means for clamping said uppercarriage on said band at a predetermined point according to the patternto be cut, means for sensing a relative movement between said band andsaid upper carriage and developing a signal when said relative movementexceeds a predetermined magnitude, and means responsive to said signaland causing a turning off of the driving means.
 3. The torch cuttingapparatus as claimed in claim 2, wherein said sensing means comprises atleast one sensor device having a pointed sensing tip adapted to abutagainst said band, a switching rod mounted for rotation about a pinmeans, means for coupling said pin means with said switching rod wherebya movement of said sensor tip means with said band causes a rotation ofsaid pin means and a displacement of said switching rod over a switchingpath.
 4. The torch cutting apparatus as claimed in claim 3, wherein saidsensing means comprises leaf spring means, said sensor tip means beingmounted on said leaf spring means coupling said sensor tip means withsaid pin means.
 5. A torch cutting apparatus as claimed in claim 3,wherein said switching means comprises an electrical switch meansmounted for sensing a displacement of said switching rod means over saidswitching path.
 6. The torch cutting apparatus as claimed in claim 5,wherein said electrical switch means is a microswitch means placed alongsaid switching path and being operable by said switching rod means whensaid switching rod means is displaced over said switching path, saidswitching path being dimensioned to correspond to the permissiblemagnitude of relative movement.
 7. The torch cutting apparatus asclaimed in claim 5, wherein said electrical switch means is anelectronic element undergoing a change in its electrical magnitude inresponse to the displacement of said switching rod over said switchingpath and developing a signal in response to such change of itselectrical magnitude to control the operation of said driving means. 8.The torch cutting apparatus as claimed in claim 3, wherein a springmeans is provided for coupling an end portion of said switching rod tosaid upper carriage means for fixing said switching rod in a nullposition in absence of a relative movement between said upper carriageand said band.
 9. The torch cutting apparatus as claimed in claim 2,wherein said sensing means comprises photo sensing means for sensing therelative movement between said upper carriage means and said band anddeveloping a signal which upon exceeding a predetermined magnitude willturn off said driving means.